Locomotives traditionally include a car body that houses one or more power units of the locomotive. The weight of the car body is supported at either end by trucks that transfer the weight to opposing rails. The trucks typically include cast or fabricated steel frames that provide a mounting for traction motors, axles, and wheel sets. Each railway truck is configured to pivotally support a base platform of the car body by way of a common bolster. Locomotives can be equipped with trucks having two, three, or four axles.
In some situations, operation of the locomotive can be less than optimal due to poor transfer of weight between axles due to traction and/or braking forces. In particular, when the locomotive is stationary, the weight on each axle is configured to be approximately equal. During operation, however, as the locomotive brakes, accelerates, and/or turns, forces can transfer from one axle to another, resulting in different axles carrying unequal loads. Wheels carrying lighter loads can lose proper traction and therefore be vulnerable to slipping. Accordingly, the varying loads on different axles can reduce the durability, stability, and reliability of the truck.
Force transfer can result from numerous factors related to truck design. For example, a significant amount of force transfer can be attributed to the arrangement of the traction motors within the truck. Typically, in two-axle trucks, the traction motors are arranged symmetrically about a center transom of the frame, with an inner end of each traction motor facing each other. An example of a four-axle articulated locomotive truck with this configuration is disclosed in U.S. Pat. No. 4,485,743 that issued to Roush et al. (“Roush”) on Dec. 4, 1984.
Although typical, the arrangement of traction motors disclosed in Roush may be less than optimal. This is because the symmetrical arrangement of traction motors can result in opposing reaction forces during operation of the locomotive. Such forces can generate moments that cause the frame to pitch and therefore result in undesirable force transfer between axles. This force transfer can limit the tractive capability of the axles when lightly loaded and overload the traction motors when the axles are heavily loaded.
The railway truck of the present disclosure solves one or more of the problems set forth above and/or other problems in the art.